FRMLS_CALC_MSG is a standard SAP Structure so does not store data like a database table does. It can be used to define the fields of other actual tables or to process "Error Messages from Calculation" Information within sap ABAP programs. This is done by declaring abap internal tables, work areas or database tables based on this Structure. These can then be used to store and process the required data appropriately. i.e. DATA: wa_FRMLS_CALC_MSG TYPE FRMLS_CALC_MSG.
The FRMLS_CALC_MSG table consists of various fields, each holding specific information or linking keys about Error Messages from Calculation data available in SAP. These include SUBRECN (RMS-FRM: Object Identifier), RECN (RMS-FRM: Object Identifier), MATNR (Material Number of an Item), PROPERTY (Formula Attribute)... See below for full list along with technical details, documentation, text table, check tables, foreign key relationships, conversion routines, relevant tcodes and example ABAP select code etc. .